Whether version constraints are an anti-pattern or not (i think they’re not, at least for libraries) is better debated in a separate thread.
The ground work for a real lock file is outlined out in Ability to promote freeze files to lock files · Issue #10784 · haskell/cabal · GitHub “I believe the critical point here is to separate further the planning and the building phase, allowing cabal-install to build an existing plan rather than re-executing the solver.”